The first B-52Ds reached SAC in the fall of 1956. The first few went to the 42nd Bombardment wing at Loring AFB, replacing the wing's initial B-52Cs. By the end of December 1956, several B-52Ds had been delivered to the 93rd Bombardment Wing.
There were problems with fuel leaks, with icing of the fuel system, and with malfunctions of the water injection pumps. The problem with the water injection pumps was eventually traced to the fact that the pumps would still keep operating even after the water tanks were empty. Installation of water sensors was the answer.
On September 26, 1958, two B-52Ds of the 28th Bombardment Wing based at Ellsworth AFB in South Dakota established world speed records over two different routes. One B-52D flew at 560.705 mph for 10,000 kilometers in a close circuit without payload; the other at 597.675 mph for 5000 kilometers, also in a closed circuit without payload.
Less than 6 months after the B-52F became involved in combat in Vietnam, the Air Force decided to convert most of its B-52Ds to conventional warfare capability for service in Southeast Asia. Foremost among the changes needed was to give the B-52D the ability to carry a significantly larger load of conventional bombs. This led to the Big Belly project which was begun in December of 1965. The project increased the internal bomb capacity from just 27 weapons to a maximum of 84 500-lb Mk 82 or 42 750 lb M117 conventional bombs. This was done by careful rearrangement of internal equipment, and did not change the outside of the aircraft. In addition, a further 24 bombs of either type could be carried on modified underwing bomb racks (originally designed for the carrying of Hound Dog cruise missiles and fitted with I-beam rack adapters and a pair of multiple ejection racks), bringing the maximum payload to 60,000 pounds of bombs, about 22,000 pounds more than the capacity of the B-52F.
B-52Ds of the 28th and 484th Bomb Wings deployed to Guam in March and April of 1966, replacing the B-52Fs. Over the next few years, 11 more B-52D wings were rotated to combat duty in Southeast Asia. These included the 7th BW, 22nd BW, 70th BW, 91st BW, 92nd SAW, 96th SAW, 99th BW, 306th BW, 454th BW, 461st BW, and 509th BW. SAC crews who ordinarily would have been assigned to the B-52G or H models were sent through an intensive two-week course on the B-52D, making them eligible for duty in Southeast Asia. The program was known as Arc Light. While on duty at Andersen AFB, the B-52Ds were assigned to the 4133rd Bomb Wing (Provisional), which had been established on February 1, 1966. Some wings actually completed three tours of duty in support of the Vietnam war.
During 1967-1969, the B-52Ds assigned to conventional warfare missions in Southeast Asia were given a set of electronic warfare updates. This was done under a program known as Rivet Rambler or Phase V ECM fit. This involved the fitting of one AN/ALR-18 automated set-on receiving set, one AN/ALR-20 panoramic receiver set, one AN/APR-25 radar homing and warning system, four AN/ALT-6B or AN/ALT-22 continuous wave jamming transmitters, two AN/ALT-16 barrage-jamming systems, two AN/ALT-32H and one AN/ALT-32L high- and low-band jamming sets, six AN/ALE-20 flare dispensers (96 flares) and eight AN/ALE-24 chaff dispensers (1125 bundles).
Camouflage paint in tan and two shades of green, still with white undersides, was applied to B-52s in 1965 when other USAF aircraft were adopting camouflage. B-52Ds assigned to combat duty in Vietnam were painted in a modified camouflage scheme with the undersides, lower fuselage, and both sides of the vertical fin being painted in a glossy black. The USAF serial number was painted in red on the fin.
In the spring of 1967, B-52Ds were sent to U Tapao Airfield in Thailand, from which they were able to complete their missions without inflight refuelling. U Tapao was initially more of a forward field than it was a main operating base, with responsibility for scheduling missions still remaining on Guam. Small numbers of aircraft were drawn from each SAC B-52D unit to support the effort in Thailand, which was vested in the 4258th Strategic Wing. By 1970, U Tapao had assumed sole responsibility for the Arc Light campaign and was home for over 40 B-52s, and it became a main operating base with a much greater degree of self-sufficiency. On April 1, 1970, the 4258th SW was inactivated and reactivated as the 307th SW at U-Tapao with no change in personnel or mission.
On February 16, 1968, the first B-52 Arc Light missions were flown out of Kadena AB on Okinawa, inaugurating a 30-month period in which three bases were involved in the B-52 effort in Southeast Asia.
The B-52D effort was concentrated primarily against suspected Viet Cong targets in South Vietnam, but the Ho Chi Min Trail and targets in Laos were also hit. During the relief of Khe Sanh, unbroken waves of six aircraft, attacking every three hours, dropped bombs as close as 900 feet from friendly lines.
Cambodia was increasingly bombed by B-52s throughout the later 1960s, although the raids were initially kept secret. This was done under the code name *Operation Menu*, and the raids were conducted in eastern Cambodia from Mar 18, 1969 until May 26, 1970. The targets were areas in Cambodia that were being used as sanctuaries and base areas of both the People's Army of Vietnam and Viet Cong forces. Both SAC and Defense Department records were falsified to report that the targets were actually in South Vietnam. The Cambodian raids were actually carried out at night under the direction of ground units using the MSQ-77 radar, which guided the bombers to the release point and told them the precise moment to release their bombs. This made the deception easier, since even the crew members aboard the bombers did not have to know what country they were bombing. However, the specific flight coordinates (longitude and latitude) of the points of bomb release were noted in the navigator's logs at the end of each mission, and a simple check of the map could tell the crews which country they were bombing. Most of the crews must have known what was going on.
The New York Times broke the story of the secret Cambodian bombings in May of 1969. This revelation lead to a series of illegal wiretaps designed to reveal the source of the leaks. Five members of Congress were informed of the operation, but they didn't tell anyone else about it. It wasn't until December of 1972 that Congress began to launch investigations. Although the secret Cambodian bombing raids were thought to be an initiative of the new Nixon administration, an official USAF report declassified by President Bill Clinton in 2000 revealied that secret Cambodian bombings had actually begun as early as 1965, when Lyndon Johnson was president. The *Menu* bombings were an escalation of these air attacks.
There were even attacks on North Vietnam itself, although at first only the very southernmost part near the Demilitarized Zone was hit. The B-52s generally avoided North Vietnamese airspace at this stage in the war, lest one of them fall victim to a SAM, which would have been a propaganda coup for North Vietnam and extremely embarrassing to the Defense Department.
On March 30, 1972, North Vietnamese forces began a massive invasion of South Vietnam, supported by artillery and tanks. On April 2, airstrikes against the North Vietnamese attack were authorized under the name Freedom Train. At first, these strikes were in support of the South Vietnamese forces, but later the restrictions against attacking North Vietnam were lifted and the effort changed to that of the interdiction of supply lines. The first of these raids against the North was a raid by 15 B-52Ds on railway yards and oil storage facilities at Vinh. Three days later, the airfields at Bai Thuong were hit. On the weekend of 15-16 April, targets near Hanoi and Haiphong were attacked. By mid-April, virtually all of North Vietnam had been cleared for bombing raids, for the first time in more than 3 years. On May 10, the name of the operation against North Vietnam was changed to Linebacker.
In April 1972 B-52Gs joined the effort. The B-52G was not nearly as well suited for combat duty in Southeast Asia as was the B-52D, since it could not carry bombs externally and did not have the Big Belly modifications that gave the D such tremendous bomb-carrying capability. In addition, the B-52G did not have as good an electronic countermeasures suite as the B-52D, and the tail gunner of the B-52D was particularly effective in being able to monitor SAM launches from the rear.
In the meantime, negotiations were underway in Paris between National Security Advisor Henry Kissinger and North Vietnamese leader Le Duc Tho, trying to establish some sort of framework under which the US could withdraw from an increasingly unpopular war and still leave some sort of military parity between North and South Vietnam. On October 23, progress in the peace talks in Paris led the US to call off all air operations above the 20th parallel, which put Hanoi and Haiphong off-limits. This effectively halted Linebacker. Unfortunately, this gave the North Vietnamese a breathing spell in order to strengthen their defenses and repair the damage to their key lines of communication.
On November 22, the first B-52 combat loss took place. B-52D serial number 55-0110 flying out of U-Tapao was hit by a SAM during a raid on Vinh. The damaged aircraft was able to nurse its way back to Thailand, but the crew were forced to abandon their bomber before reaching base. The was the first B-52 to be destroyed by hostile fire in more than seven years of operation.
By early December of 1972, it was clear that the Paris peace talks were going nowhere, and President Richard Nixon decided that more drastic means were necessary. He ordered a new, full-scale aerial assault on North Vietnam in order to bring "peace with honor", as it was known in those days. The code name for the assault was Linebacker II. Air bases, missile sites, oil storage facilities, ammunition dumps and railroad networks would be struck. For the first time, targets in and around Hanoi and Haiphong would be attacked by the B-52s.
The first Linebacker II raid was on December 18, 1972, an attack on North Vietnamese fighter bases at Kep, Hoa Lac and Phuc Yen, plus the railhead at Yen Vien and the warehouse and storage complex at Kinh No.
During the Linebacker II raids, strict rules of engagement were enforced to lessen the risk of hitting civilian areas, as well as to avoid striking areas where POWs were known to be housed. In addition, B-52s were prohibited from maneuvering to evade SAMs or fighters once they had passed the initial point and were approaching the bomb release point. Initially, losses were heavy, with three B-52s being lost on the first night, and no less than 6 on the second night. Several hundred SAMs were fired at B-52s during the 11 days of Linebacker II. Onboard ECM equipment provided some protection, but it was far from infallible. In the latter stages of Linebacker II, more attention was paid to SAM sites and suspected missile storage areas, and the loss rate began to decline.
Linebacker II ended on December 29, 1972, when North Vietnam returned to the conference table. By this time, the North Vietnamese were clearly at the mercy of the B-52s. Had the bombing continued, there would have been little danger from SAMs. During Linebacker II, a total of 729 B-52 sorties were flown, 34 targets were hit, 15,287 tons of bombs were dropped, 1600 military structures had been damaged or destroyed, 3 million gallons of petroleum had been destroyed, and about 80 percent of North Vietnam's electrical generating capacity had been knocked out.
15 B-52s were lost during Linebacker II, with 9 being B-52Ds and 6 B-52Gs. This corresponded to a loss rate of less than 2 percent of the sorties. All 15 of the B-52s lost in Linebacker were shot down by SAMs, and none by fighters or AAA. Five MiGs were claimed by B-52 tail gunners during Linebacker II, but only two of them were actually confirmed.. The B-52 raids seemed to have the desired effect of getting North Vietnam to negotiate seriously, and on January 21, the agreement ending the American role in the war took effect on January 23, 1973. American POWs were released in March.
After Linebacker II, the B-52s returned to Arc Light missions. The last such mission took place on August 15, 1973. All the B-52s were withdrawn from Southeast Asia shortly thereafter.
On December 8, 1965, Secretary of Defense Robert S. McNamara had announced a long-term phaseout program involving several versions of the B-52 and their replacement by the General Dynamics FB-111A. Under the original plan, all remaining B-52C, D, E, and F aircraft were to be gone by the middle of 1971. However, because of the demands of the Vietnam War, the B-52D lasted much longer than expected, remaining in service several years after most of the other "tall-tailed" Stratofortresses had been retired. The B-52D fleet remained virtually intact until late 1978, when 37 examples were retired to storage at Davis-Monthan AFB. The final phaseout of the B-52D took place in 1982/83 when over 50 were sent to storage. Several were sent to join museum collections across America and even overseas.
The following outfits flew the B-52D:
Direct Wing control 1970-73 - replaced 4258 SW
Direct wing control 1970 - replaced 4252 SW. *Arc Light*
missions from this base terminated 9/70.
Possible that it exercised operational control over the
B-52Ds at Kadena from 2/68. Inactivated 4/1/70 and
replaced by 376 SW
Possible that it exercised operational control over the B-52Ds at U-Tapao from 4/67. Inactivated 4/1/70 and reorganized as 307 SW